Among conventional methods of recognizing the substance of an image, such as “successful passing shot” and “successful smash”, contained in a scene of a sports picture of, for example, tennis, there are known methods of recognizing the substance of such an image by manually inputting a “successful passing shot” section, a “successful smash” section and a like section of picture information one by one, or by extracting positions of respective of a ball, players and court lines and totally judging a change with time in spatial correlations among the extracted positions with use of a computer.
The method of image recognition based on manual input, however, involves a problem of increased labor costs and a problem of heavy burden on the operators which arises when the contents processing takes a long time, though the substance of an image can be reliably recognized. On the other hand, the method of automatic image recognition with a computer has a difficulty in judging whether the ball is on line or out particularly when the ball falls to the ground adjacent a line.